Leverage pulley



- Sept. 6, 19 A. R. LOFSTRAND LEVERAGE' PULLEY Original Filed Aug. 19,1945 Patented Sept. 6, 1949 2,486,8 Iij v -I4EVERAGE PUBLEYAndetsefiLofstrand, SilverlSpring, I Original "application "August 19,"1943,- Serial %No; 1 4993271. Divided"and this application August 2 '14,1946, Serial No; 690,504

' This invention: relatesatorwindingsdrums and; the like =and;isia,divisionsof myi present appliea- Glassware-washing machines..= I

vIn a glassware mashingqmachine set :forth ini myabove-1mentionedzpriorcapplication;pthere isprovided:sanlelevatorefersraislngsandlowering.v

the:g1assware;intoandifroma washing tub. The weight of the elevator isbalanced or compensated by a spring whichis fixedon to the machine andthGaBleVAtOli is ,connected, .to tha spring by a cable or cord trainedover a plllley iirsucmar manner that as the elevator is lovvered a compression force-is exerted on thespring tending to return the elevatortositsgraised or original,

o n: Br s n a eqav iem i eyr'fq s leli e iqe ap lied t masterin i-tense: quent return force applied to the cable would increaseproportionately with the travel of the elevator, so that by the time theelevator had reached the lowest limit of its travel a very great returnforce would be applied and it would require much strength to hold theelevator in this position.

The most desirable condition in an elevator of this kind would be tohave a. constant return force applied to the elevator. It is realizedthat such a constant force may be applied by the use of a compensatingweight in place of the spring, but the disadvantages of using such aweight do not justify its use, for the weight is much more awkward tohandle and requires more room in which to operate than a springstructure. By using a lever pulley so designed as to permit the cable tobe trained over it and that more cable leaves the pulley on the elevatorside than comes onto the pulley on the spring side and that the amountof cable leaving the pulley increases with rotation thereof while theamount going on remains constant, the advantages of both the springcompensating means and the weight balancing means are utilized and theirdisadvantages are minimized.

It is, therefore, an object of this invention to provide a leveragepulley of the kind hereinafter described, whereby the increase of returnspring force on the compensating spring will vary in inverse relation tothe travel of the elevator so as to provide a substantially constantreturn force on the elevator.

Another object of this invention is to provide a spiral pulley or platewhich may be used with a conventional symmetrical pulley to achieve theresult as set forth above.

Still another object of this invention is to provide a spiral pulleymounted adjacent to-a conventionalcircular pul ley, and a transferoradapter -plate--for;trainin g: thecord from the -;circular.to thespiral ,;p ulley-,

for thepurpose as herein set forth.

:With, .the above and otherobjeots; in viewg; my;

invention consists in:the;arrangement combina tion; and details ofvconstruction :disclosed lin the, drawings and specification, andthen-:more par ticularly pointed out: inzthe a pendedzclaim In the,drawin s .-Whe1fein;-:.similar reference characters I designate,si-milahmpallts throughout. the; respective views,

- :Eigu-re .1 is a 1side;.e1evatiQn::0f;-,a;leverage ,p llley:constructed ,according .;to =,an ;embodiment of my, inventiom, e

Figure -2 PiSI an: end

rfiisur Figure 3 is a vertical section taken on the line 33 of Figure 1,

Figure 4 is a vertical section taken on the line 44 of Figure 1.

Referring to the drawings; the numeral 10 designates generally aleverage pulley constructed according to an embodiment of thisinvention, particularly adapted for use with the glassware washingmachine as set forth in my copending application as set forth above.

The leverage pulley l0 comprises a plate ll, an annular pulley I2, and atransfer block M. The plate II is formed of a flat plate of asubstantially spiral configuration, the spiral outline extendingapproximately three hundred and sixty degrees around a bushing 15. Theplate ll between the extremities of the periphery thereof is formed witha cut-out Or recess l6 providing a reduced part I! at the outermost endof the spiral plate II. The plate II has a groove I8 about the outeredge thereof which terminates at the inner portion of the reduced partll. The plate II is further formed on one side with an opening l9therethrough above the inner end of the recess [6 and oppositelyinclined grooves 20 and 2| extending from the opening H) to the outerend of the recess IS. A groove 22 on the other side extends from theopening l9.

An annular grooved pulley I2 is disposed in face abutting relation tothe spiral pulley H and is secured on a cylindrical bushing I5 whichextends through both pulleys H and I2.

An arcuate block M is secured to the pulley II by fastening members 24and is formed with a groove 25 on the outer edge thereof in which acable 26 is adapted to be engaged.

In the use of this pulley ID, the cable 26 zviewzs en'; from:- the rightor plate which-- may= bev 3 brought upwardly over a P r f th annularpulley l2, reverted onto the block H, through groove 22, hole l9,grooves 20 and 2|, and is reverted again over the arm I1 and through thegroove I8 about plate ll, thence downwardly to the elevator. In thismanner the movement down of the elevator will cause the pulley II! torotate clockwise, increasing the lever arm on the elevator side, therebyproviding for an increase in elevator downward travel upon rotation ofthe pulley 10 while the increase oi. spring tension on the other end ofthe cable 26 remains constant. 7

I do not mean to confine myself to the exact details of constructionherein disclosed but claim all variations falling within the purview ofthe appended claims.

Having thus described my invention, what I claim is:

1. A leverage pulley comprising a plate of substantially spiralconfiguration having a groove in the outer edge thereof, an annulargrooved pulley secured to One face of said plate, and a block secured tosaid plate and formed with a longitudinally curved grooved outer edge,said plate having an opening therethrough whereby a cable may beextended from'the grooved outer edge of said block through said openingand into the groove of said plate.

2. A leverage pulley comprising a plate of substantially spiralconfiguration having a groove in the outer edge thereof, an annulargrooved pulley on one side of said plate, a bushing securing said plateand annular pulley together, a block having an inner edge substantiallycontacting with an edge of said pulley, and means securing said block tosaid plate, said block having a grooved longitudinally curved outeredge, said plate having an opening therethrough adjacent one end of saidblock whereby a cable may be trained partially about said annular pulleyunderneath said block, over the groove in said block, through saidopenin and then trained in the groove of said plate starting from saidlever arm.'

3. A leverage pulley comprising a plate of substantially spiralconfiguration, having a groove in the outer edge thereof, said platebeing formed with a cut-out between the extremities of said groove, andan opening on one side thereof, said plate being formed with a secondgroove communicating between said opening and said cutout, an annulargrooved pulley secured to one .face of said plate, and a grooved blocksecured to said plate adjacent said annular pulley for training a cablefrom said annular pulley into said REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,178,122 Ostler et a1. Oct. 31,1939 2,081,737

Chlttick May 23, 1937

